old imac as server

[lil'homunculus]

just got a new/old imac with 3.5 Gb of free energy.
have hooked it up to my MBP as a server but cannot access the full system nor can it do the same for me. I'm at a point where i can play music, look at pictures, etc...
however, i'd like to surf from this computer and add/delete files. Someone here has all of the answers...
How do i make this little monster become a true server?

 

[NAG]

What OS are you running and can you be a little more exact as to what your network is set up like? (Do you have a router or are these machines just connected to each other and if so are you using a cross over cable.)